Verb

To lie in a position directly beneath.

A stratum of clay underlies the surface gravel.

To lie under or beneath.

To serve as a basis of; form the foundation of.

a doctrine underlying a theory

*{{quote-magazine, year=2013, month=July-August, author= Sarah Glaz

, title= Ode to Prime Numbers , volume=101, issue=4, magazine=(American Scientist) , passage=Some poems, echoing the purpose of early poetic treatises on scientific principles, attempt to elucidate the mathematical concepts that underlie prime numbers. Others play with primes’ cultural associations. Still others derive their structure from mathematical patterns involving primes.}}

To be subject to; be liable to answer, as a charge or challenge.

* Sir Walter Scott

The knight of Ivanhoe underlies the challenge of Brian der Bois Guilbert.

(mining) To underlay.

Verb

(label) To take upon oneself; to start, to embark on (a specific task etc.).

*(John Milton) (1608-1674)

*:To second, or oppose, or undertake / The perilous attempt.

(label) To commit oneself (to an obligation, activity etc.).

:

*(William Shakespeare) (c.1564–1616)

*:I'll undertake to land them on our coast.

(label) To overtake on the wrong side.

:

To pledge; to assert, assure; to dare say.

*, Bk.VII:

*:"I have now aspyed one knyght," he seyde, "that woll play hys play at the justys, I undirtake ."

*(William Shakespeare) (c.1564–1616)

*:And those two counties I will undertake / Your grace shall well and quietly enjoiy.

*(John Dryden) (1631-1700)

*:And he was not right fat, I undertake .

* (1665-1728)

*:I dare undertake they will not lose their labour.

To take by trickery; to trap, to seize upon.

*:

*:there came fourty knyghtes to sire Darras // So sire Tristram endured there grete payne / for sekenesse had vndertake hym / and that is the grettest payne a prysoner maye haue

(label) To assume, as a character; to take on.

:(Shakespeare)

(label) To engage with; to attack.

*(William Shakespeare) (c.1564–1616)

*:It is not fit your lordship should undertake every companion that you give offence to.

(label) To have knowledge of; to hear.

:(Spenser)

(label) To have or take charge of.

*(Geoffrey Chaucer) (c.1343-1400)

*:Keep well those that ye undertake .

*(William Shakespeare) (c.1564–1616)

*:who undertakes you to your end